ARROW-11414: [Rust] Reduce copies in Schema::try_merge#9347
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alamb wants to merge 1 commit intoapache:masterfrom
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ARROW-11414: [Rust] Reduce copies in Schema::try_merge#9347alamb wants to merge 1 commit intoapache:masterfrom
alamb wants to merge 1 commit intoapache:masterfrom
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alamb
commented
Jan 28, 2021
| /// use arrow::datatypes::*; | ||
| /// | ||
| /// let merged = Schema::try_merge(&vec
houqp
approved these changes
Feb 2, 2021
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Yes I like this approach a lot |
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I was looking at this code yesterday while using it in IOx -- https://github.com/influxdata/influxdb_iox/pull/703
Rationale:
Even though
Schema::try_mergerequires a slice ofSchemas (not schema refs) ownership of its inputs, it copies all of its fields. This is inefficient ideal in the common case where most of the fields in the mergedSchemawill be the sameChanges:
This PR proposes to change the implementation so that
try_mergetakes something (like aVec) that can iterate over the Schemas passed in and consume them, avoiding at least one copy per unique field. I intend no algorithmic changes, only performance improvement.